WO2011027471A1

WO2011027471A1 - Solid laser-exciting module for flat waveguide laser

Info

Publication number: WO2011027471A1
Application number: PCT/JP2009/065577
Authority: WO
Inventors: 修平山本; 嘉仁平野; 俊行安藤; 陽介秋野; 武司崎村; 隆行柳澤
Original assignee: 三菱電機株式会社
Priority date: 2009-09-07
Filing date: 2009-09-07
Publication date: 2011-03-10

Abstract

Disclosed is a solid laser-exciting module for a flat waveguide laser device, which is provided with a flat laser medium for amplifying a laser light introduced, while propagating same in a direction along a pair of side faces (33 and 34) and reflecting same between the side faces. One face (33) of the pair of side faces is inclined at a predetermined taper angle with respect to a predetermined direction so that the spacing from the other side face (34) extending in the predetermined direction may become gradually wider. The laser light, which is introduced into the laser medium from a predetermined portion of the pair of side faces on the side where the spacing between the side faces is wider, propagates in the laser medium while being reflected between the side faces. The laser beam makes a turn on the side where the spacing between the side faces is narrower in the laser medium, propagates again to the side where the spacing between the side faces is wider, and then is outputted.

Description

Solid-state laser pumping module for planar waveguide lasers.

The present invention relates to a measurement device using a laser, a processing laser device, a high-power laser device suitable for a light source such as a printer or a projection television, and more particularly to a solid-state laser excitation module for a planar waveguide laser.

For example, the shape of a solid-state laser medium used in a solid-state laser as shown in Non-Patent Document 1 below generally includes a rod type, a slab type, a disk type, a planar waveguide type, a two-dimensional waveguide type, and a fiber type. Among these, rod type, slab type, disk type, planar waveguide type, etc. introduce pumping light from the side surface or laser end face, generate gain, configure laser oscillator or laser amplifier, and obtain laser output .

Here, when high-power excitation is performed to obtain a high-power laser output, since the amplification gain in the laser medium increases, parasitic oscillation and parasitic amplification occur, and energy is consumed. Laser power and efficiency may be reduced. The cause of parasitic amplification and parasitic oscillation is that the optical path length of laser light passing through the laser medium is shorter than the optical path length of parasitic oscillation and parasitic amplified light in a laser oscillator or laser amplifier. For this reason, in general, the total reflection part in the laser medium is used as a roughened surface so that parasitic oscillation and parasitic amplification do not occur, and the propagation path length of parasitic oscillation and parasitic amplified light is shortened. May be suppressed.

However, with this configuration, it becomes impossible to reflect the laser beam to be amplified by using the roughening surface as a total reflection surface. As a result, the laser optical path in the laser medium is limited, and a long optical path length is obtained. Since it cannot be obtained, a high amplification factor cannot be obtained, and the laser output and efficiency may be lowered. Furthermore, since the amplification factor of the laser is low, parasitic oscillation and parasitic amplification generation threshold are low, and parasitic oscillation and parasitic amplification are likely to occur.

On the other hand, in the two-dimensional waveguide type or fiber type, light confinement is performed by the refractive index distribution in the two-dimensional direction of the cross section of the laser light, and the traveling direction of the light is the one-dimensional direction. For this reason, since the optical path of parasitic oscillation or parasitic amplification is equal to the optical path of laser oscillation or laser amplification, there is a feature that parasitic oscillation or parasitic amplification is difficult to occur. However, since the cross-sectional area of the laser medium is small, it is difficult to introduce excitation light, and a complicated configuration is required. Therefore, there are features such as high cost and low reliability.

Generally, there is a disk type as a form using a flat plate laser medium. In the disk type, laser light is introduced from a flat plate surface, and the laser light is amplified when passing through a thin laser medium or reflecting and reciprocating. In such a case, the laser amplification gain is small because the passing distance of the laser medium is short. For this reason, the optimum output mirror reflectivity is increased in the laser oscillator. In such a case, there is a feature that the output is reduced by a slight loss in the resonator. Further, when used as an amplifier, the amplification factor is small, so that the efficiency is low, or multipath may be used for the purpose of improving the efficiency, but the configuration is complicated. Further, since the propagation length in the disk-shaped flat plate surface is longer than the thickness direction, parasitic oscillation and parasitic amplification in the flat plate surface are likely to occur. For this reason, there is a feature that it is difficult to increase the output. As described above, since the disk type is likely to cause parasitic oscillation and parasitic amplification, it is difficult to increase the output, and a complicated parasitic oscillation suppressing structure is required.

Generally, in a slab type laser medium, excitation light is introduced from the side or end face, and laser light is introduced from the end face. Further, the laser beam is output from the end surface facing the end surface to which the laser beam is introduced. In some cases, laser light propagates in a zigzag manner in the slab type laser medium to increase the optical path length. Further, by propagating in this zigzag manner, the thermal lens effect generated in the laser medium may be averaged and reduced.

However, in such a case, a region where there is no overlap between the laser beam and the laser medium is generated due to propagation in a zigzag manner. For this reason, the extraction efficiency is low. Furthermore, since the gain in a portion where energy is not extracted is high, parasitic oscillation and parasitic amplification are likely to occur. Further, there is a feature that parasitic oscillation is likely to occur in a reciprocating optical path between two opposing surfaces of the zigzag reflecting surface. As described above, the zigzag slab type is prone to parasitic oscillation and parasitic amplification, so that it is difficult to increase the output, and a complicated parasitic oscillation suppressing structure is required.

In this type of conventional high-power laser device, when the laser medium has a rod type, slab type, disk type, planar waveguide type, etc., the optical path of parasitic oscillation or parasitic amplification is higher than the optical path of laser oscillation or laser amplification. Since it is long, parasitic oscillation and parasitic amplification occur at the time of high output excitation, and there are problems such as a decrease in laser output and efficiency.
Furthermore, when the laser medium has a two-dimensional waveguide type or fiber type, since the cross-sectional area of the laser medium is small, it is difficult to introduce pumping light and a complicated configuration is required. There was a problem such as low.

The present invention has been made to solve the above-described problems, by suppressing parasitic oscillation and parasitic amplification, obtaining the longest laser amplification optical path, and performing high output excitation with a simple excitation configuration. An object of the present invention is to provide a solid-state laser excitation module for a planar waveguide laser device that obtains a high-efficiency and high-power laser output.

The present invention includes a flat plate-shaped laser medium that propagates an amplified laser beam in a direction along the side surface while reflecting between the pair of side surfaces and amplifies the laser beam between the pair of side surfaces, and one side surface of the pair of side surfaces is in a predetermined direction. And inclined at a predetermined taper angle with respect to the predetermined direction so as to gradually widen the distance from the other side surface extending along the side of the pair of side surfaces. The laser light introduced into the laser medium is propagated in the laser medium while reflecting between the side surfaces, and is further folded back on the side having a narrow side surface interval in the laser medium and propagated again to the side having a large side surface interval for output. The solid-state laser pump module for the planar waveguide laser device is characterized.

In the present invention, a solid-state laser excitation module that obtains a high-efficiency and high-output laser output by suppressing parasitic oscillation and parasitic amplification, obtaining the longest laser amplification optical path, and performing high-output excitation with a simple excitation configuration. Can be provided.

1 is a top view of a planar waveguide laser device including a solid-state laser excitation module according to Embodiment 1 of the present invention. FIG. 2 is a side view of the planar waveguide laser device of FIG. It is a side view of the planar waveguide type laser apparatus containing the solid-state laser excitation module by Embodiment 2 of this invention. It is a side view of the planar waveguide type laser apparatus containing the solid-state laser excitation module by Embodiment 3 of this invention. It is a side view of the planar waveguide type laser apparatus containing the solid-state laser excitation module by Embodiment 4 of this invention. It is a side view of the planar waveguide type laser apparatus containing the solid-state laser excitation module by Embodiment 5 of this invention. It is a top view of the planar waveguide type laser apparatus containing the solid-state laser excitation module by Embodiment 6 of this invention. It is an enlarged view of the area | region C shown with the broken line of FIG. It is a top view of the planar waveguide type laser apparatus containing the solid-state laser excitation module by Embodiment 7 of this invention. It is a top view of the planar waveguide type laser apparatus containing the solid state laser excitation module by Embodiment 8 of this invention. It is a top view of the planar waveguide type laser apparatus containing the solid-state laser excitation module by Embodiment 9 of this invention. It is a top view of the planar waveguide type laser apparatus containing the solid-state laser excitation module by Embodiment 10 of this invention. It is a figure for demonstrating the beam of an actual laser beam. It is a top view for demonstrating the structure of the input / output part of the laser beam of the solid-state laser excitation module by this invention. It is a fragmentary figure which shows another example of a structure of the input / output part of the laser beam of the solid-state laser excitation module by this invention. It is a fragmentary figure which shows another example of the structure of the input / output part of the laser beam of the solid-state laser excitation module by this invention. It is a fragmentary figure which shows another example of the structure of the input / output part of the laser beam of the solid-state laser excitation module by this invention. It is a partial side view which shows an example of a structure of the introduction part of the excitation light of the solid-state laser excitation module by this invention. It is a partial side view which shows another example of a structure of the introduction part of the excitation light of the solid-state laser excitation module by this invention. It is a partial side view which shows another example of a structure of the introduction part of the excitation light of the solid-state laser excitation module by this invention. It is a partial side view which shows another example of a structure of the introduction part of the excitation light of the solid-state laser excitation module by this invention. It is a partial side view which shows another example of a structure of the introduction part of the excitation light of the solid-state laser excitation module by this invention. It is a partial side view which shows another example of a structure of the introduction part of the excitation light of the solid-state laser excitation module by this invention.

Hereinafter, a planar waveguide laser device according to the present invention will be described with reference to the drawings based on preferred embodiments. Note that the same or corresponding parts in the respective embodiments are denoted by the same reference numerals and redundant description is omitted.

Embodiment 1 FIG.
1 is a top view of a planar waveguide laser device including a solid-state laser excitation module according to Embodiment 1 of the present invention, and FIG. 2 is a side view of the planar waveguide laser device of FIG. However, in both figures, the solid-state laser pumping module 100 between the semiconductor lasers 1 which are pumping sources on both sides is a cross-sectional view taken along the line AA in FIG. 2, and in FIG. Is shown in a cross-sectional view along

1 and 2, the solid-state laser excitation module 100 includes a laser medium 3 and a pair of clads 4a and 4b that are respectively joined to a pair of

main surfaces

31 and 32 of the laser medium 3 that face each other in parallel. The laser light bonded onto the side surfaces 33 and 34 has a total reflection film 6 that reflects the light, and a part of the side surface 34 includes an antireflection film 7 that transmits the laser light instead of the total reflection film 6. A pair of end faces 35 and 36 of the laser medium 3 facing each other in parallel introduce the excitation light 2 from the semiconductor laser 1.

As the laser medium 3, a general solid laser material can be used. For example, Nd: YAG, Nd: YLF, Nd: Glass, Nd: YVO4, Nd: GdVO4, Yb: YAG, Yb: YLF, Yb: KGW, Yb: KYW, Er: Glass, Er: YAG, Tm: YAG, Tm: YLF, Ho: YAG, Ho: YLF, Tm, Ho: YAG, Tm, Ho: YLF, Ti: Sapphire, Cr: LiSAF, etc. are used. These solid laser materials may be ceramics in addition to crystals. Moreover, glass may be sufficient. Further, a solid laser material in which an active medium not described above is added to a base material not described above may be used.

The laser medium 3 is a planar waveguide type and has a shape of a flat plate having a thin thickness in one axial direction. Here, for the sake of explanation, the thickness direction of the laser medium 3 is taken as the z axis, and the two axes in the plane of the laser medium 3 are called the x axis and the y axis as shown in FIG. 1, and the three axes are orthogonal to each other. Use a coordinate system.

The laser medium 3 has a quadrangular shape in the xy plane parallel to the

main surfaces

31 and 32. Here, the pair of opposing side surfaces 33 and 34 are not parallel, and the side surface 33 is inclined with respect to the side surface 34 along a predetermined direction at a taper angle θ1 in the xy plane. That is, the one side surface 33 is inclined at a predetermined taper angle with respect to the predetermined direction so that the interval between the one side surface 33 and the other side surface 34 extending along the predetermined direction gradually increases. A total reflection film 6 that reflects laser light is provided on the side surface 34 of the laser medium 3, and an antireflection film 7 that transmits laser light is further provided in part. On the side surface 33, a total reflection film 6 for reflecting laser light is applied to the entire surface. With this structure, as will be described later, the laser light propagates in one round-trip while being reflected between the side surfaces 33 and 34 in the laser medium 3.

The

clads

4a and 4b shown in FIG. 2 have a refractive index smaller than that of the laser medium 3, and are respectively joined to

main surfaces

31 and 32 parallel to the xy plane of the laser medium 3. The

claddings

4a and 4b are configured by, for example, depositing a film made of an optical material as a raw material or optically bonding the optical material to the laser medium 3 by optical contact or diffusion bonding. The

clads

4a and 4b may be bonded to a substrate (not shown). Further, the substrate may be bonded to a heat sink (not shown). The substrate and the heat sink may be on one side of the xy plane of the laser medium 3 or may be bonded to both sides of the two opposing surfaces.

The semiconductor lasers 1 on both sides are arranged close to the end faces 35 and 36 of the laser medium 3, and although not shown, a cooling heat sink is joined as necessary. The size of the semiconductor laser 1 in the x-axis direction is substantially equal to the size of the laser medium 3 in the x-axis direction, and pumping light is output substantially uniformly in the x-axis direction. The semiconductor laser 1 outputs excitation light 2. Here, the semiconductor laser 1 that outputs the excitation light 2 may be a multi-emitter semiconductor laser in which a plurality of active layers are arranged in the x-axis direction. In this case, since a plurality of LD (laser diode) lights are output from the plurality of active layers, a plurality of laser output lights (excitation light) arranged in the x-axis direction can be obtained. Further, the active layer of the semiconductor laser 1 may be a broad area LD that is wide in the x direction.

Next, the operation will be described. The excitation light 2 output from the semiconductor laser 1 enters the laser medium 3 from the end faces 35 and 36 of the laser medium 3 and is absorbed by the laser medium 3 while propagating in the y direction (corresponding to a predetermined direction). When the pumping light 2 is absorbed by the laser medium 3, a gain for the laser light is generated inside the laser medium 3. Due to the gain generated in the medium 3 in the laser, the laser light passing therethrough is subjected to an amplification action, and the laser output increases. A laser seed light is prepared, introduced into the laser medium 3 and amplified so that it becomes a laser amplifier, and an output mirror (not shown) that reflects a part of the laser light is arranged on the laser optical axis so as to be perpendicular to the axis. By doing so, it becomes a laser oscillator. For this reason, the following description applies to both the laser oscillator and the laser amplifier unless otherwise specified.

Here, the laser incident light 8 is introduced into the laser medium 3 from the antireflection film 7 that transmits the laser light on the side surface 34. The laser incident light 8 is inclined by θin0 in the xy plane with respect to the vertical line of the antireflection film 7. Here, when the refractive index of the laser medium 3 is n, the inclination angle of the laser incident light 8 introduced into the laser medium 3 in the xy plane with respect to the vertical line of the antireflection film 7 is θin1 = Sin ⁻¹ (1 / N · Sinθin0). The laser incident light 8 is introduced with an inclination with respect to the vertical line of the side surfaces 33 and 34 in the xy plane. The laser incident light 8 that has entered the laser medium 3 is reflected by the total reflection film 6 that propagates in the laser medium and reflects the laser light applied to the side surface 34 and the side surface 33 facing the side surface 34. Since the laser incident light 8 is introduced with an inclination with respect to the vertical line of the side surfaces 33 and 34 in the xy plane, the laser light reflected by the side surface 33 does not return to the antireflection film 7 but the antireflection film on the side surface 34. 7 hits the total reflection film 6 at a position adjacent to 7 and reflects again. As described above, the laser beam propagating through the laser medium 3 is reflected by the total reflection film 6 on the side surfaces 33 and 34 while being repeatedly reflected between the side surfaces 33 and 34 as indicated by the laser reflected light 10 in FIG. Is done.

The side surface 33 is within the xy plane with respect to the side surface 34 so that the distance between the side surfaces 33 and 34 is wider at one end side where the antireflection film 7 of the side surface 34 is applied than at the other end side of the side surface 34. Inclination angle (taper angle) θ1 is inclined. For this reason, every time the laser beam incident from the antireflection film 7 is reflected by the side surface 33, the sum of the incident angle and the reflection angle at the side surface 34 of the laser reflected light 10 is reduced by 2θ1. Therefore, the laser reflected light 10 is repeatedly reflected while the interval between the reflection positions of the laser reflected light 10 on the side surfaces 33 and 34 is narrowed, and the reflection angle at the side surface 34 approaches 0, that is, perpendicular to the side surface 34. .

When the reflection angle at the side surface 34 becomes vertical, the laser reflected light 10 is folded back within the laser medium 3 by the taper angle θ1 of the side surface 33. The reflected laser reflected light 10 is repeatedly reflected between the side surfaces 33 and 34 by the total reflection film 6 again. In the return path, the sum of the incident angle and the reflection angle at the side surface 34 increases 2θ1 each time the side surface 33 reflects. Then, the laser reflected light 10 is propagated while increasing the interval between the reflection positions of the laser reflected light 10 on the side surfaces 33 and 34. In this way, the return path is finally output as the laser output light 9 from the antireflection film 7 on the side surface 34 while passing through the optical path substantially the same as the forward path.

Here, the angle in the xy plane of the laser incident light 8 introduced from the antireflection film 7 with respect to the vertical line of the antireflection film 7 is θin1, and the refractive index of the laser medium 3 is n. At this time, the maximum value of the internal incident angle θin1 of the laser incident light 8 is equal to the internal total reflection angle and θin1max = Sin ⁻¹ (1 / n). For example, when the laser medium 3 is Nd: YAG, the maximum internal incident angle θin1max = 33.3 degrees. Here, if the number of reflections per side surface (33, 34) on one side in the laser medium 3 is m, the inclination angle θ1 of the side surface 33 with respect to the side surface 34 is θ1≈θin1 / (2 (m−1)). An angle satisfying (≈: substantially equal) is set. For example, if the laser medium is Nd: YAG, the internal incident angle of the laser beam is the maximum angle θin1max, and the number of reflections is 10, then θ1≈1.85 degrees. In order to improve the beam overlap efficiency in the laser medium 3, the incident angle of the laser incident light 8 should be small. In addition, it is better that the number of reflections m is larger. For this reason, for example, when the internal incident angle θin1 of the laser incident light 8 is 5 degrees and the number of reflections is 20, the inclination is θ1≈0.13 degrees.

As described above, the inclination angle θ1 between the side surfaces 33 and 34 depends on the length in the y direction in the xy plane of the laser medium 3, the width in the x direction, the beam width w of the laser light, the width of the antireflection film 7, and the like. The wrap efficiency is set to be high and the number of reflections is increased. As described above, such an angle is mainly set to an inclination angle θ1 <2 degrees between the side surfaces 33 and 34.

As described above, since the inclination angle between the side surfaces 33 and 34 is set to θ1, the interval at which the laser beam is reflected by the side surface 33 or the side surface 34 in the forward path becomes shorter as the reflection is repeated. For this reason, the beam overlap efficiency between the laser medium 3 and the laser light is increased. Further, near the turning point of the laser beam, the laser beam passes many times through the adjacent points, so that the beam overlap efficiency is higher, and as a result, the extraction efficiency of the laser is increased, resulting in high efficiency and high output. Laser light is obtained.

1 and FIGS. 7 to 12, the main axis of the laser beam is displayed. In practice, however, the laser beam is introduced from the antireflection film 7 with a wide beam as shown in FIG.

According to this configuration, since the optical path length of the laser light (laser reflected light 10) in the laser medium 3 can be maximized, parasitic oscillation and parasitic amplification are difficult to occur. Since the side surfaces 33 and 34 are inclined at an angle θ1, there is no optical path that circulates between the two opposing surfaces. For this reason, the optical path in the laser medium 3 having the longest parasitic oscillation or parasitic amplified light is the same optical path as the laser reflected light 10 from the vicinity of the antireflection film 7 on the side surface 34. In general, since the optical path length of parasitic oscillation and parasitic amplification light is longer than the optical path of laser light, when a large gain is generated with an increase in excitation output, extraction of energy due to parasitic oscillation and parasitic amplification becomes large, and laser output power is increased. Incurs efficiency loss. On the other hand, in this configuration, the longest optical path of parasitic oscillation and parasitic amplification is substantially the same as the laser reflected light optical path, so that even when the gain increases as the pumping output increases, the amplification of the laser light increases as well. Therefore, the amplification factor of the laser beam is not exceeded. For this reason, high-efficiency and high-power laser light can be obtained even during high-power excitation.

Since the forward path and the return path of the laser beam are substantially the same, separation using the polarization of the laser beam can be performed using the separation means 50 as shown in FIG. The separating means 50 may transmit the laser incident light 8 and reflect and separate the laser output light 9. Alternatively, the separating means 50 may reflect the laser incident light 8 and transmit the laser output light 9 to be separated. You may do. The separating means 50 can be composed of a polarizer 51 and a quarter wavelength plate 52 as shown in FIG. 15, for example. The linearly polarized laser incident light 8 is circularly polarized by the quarter wavelength plate 52 and introduced into the laser medium 3. When the laser incident light 8 is output, it passes through the quarter-wave plate 52 again, so that the laser output light 9 becomes a polarization direction of linearly polarized light whose polarization direction is orthogonal to the laser incident light 8. For this reason, it becomes separable by the polarizer 51.

Further, as shown in FIG. 16, the separating means 50 may be constituted by an isolator 54. For example, after passing through an isolator 54 including a polarizer 51 and a 45 degree Faraday rotator 53, laser light is introduced into the laser medium 3. The laser light amplified by reciprocating in the laser medium 3 exits the laser medium 3 and again passes through the Faraday rotator. Since the polarization of the laser light that has passed through the Faraday rotator is rotated by 90 degrees with respect to the incident light, it is separated from the incident light by the polarizer. When incident light passes through the polarizer, the output light is reflected by the polarizer, and when incident light is reflected by the polarizer, the output light passes through the polarizer. The laser light introduced into the laser medium 3 is linearly polarized light inclined by 45 degrees by the Faraday rotator.

Further, as shown in FIG. 17, a half-wave plate 55 may be arranged between the Faraday rotator 53 and the laser medium 3 in the configuration of FIG. With the half-wave plate 55, the linearly polarized light inclined at 45 degrees can be converted into linearly polarized light that is parallel or orthogonal to the flat plate surface (main surface) of the laser medium 3. Since the half-wave plate is reversible, the incident light before passing through the half-wave plate and the output light passing through the half-wave plate 55 have the same polarization direction and a polarization direction inclined by 45 degrees. . For this reason, polarization separation can be performed by the isolator 54 as in the case where the half-wave plate 55 is not disposed. As described above, since the linearly polarized light is parallel or orthogonal to the main surface of the laser medium 3, for example, even when the laser medium 3 has different gains or different amplification wavelengths with respect to different polarization directions, Can be amplified.

Thus, by using the separating means 50, it is possible to separate the laser incident light and the laser output light which are substantially the same optical path. Such separation can be used in both laser oscillator and laser amplification configurations, but is particularly effective when used as a laser amplifier.

When the total reflection film 6 is used as a laser oscillator, a high reflectance is set with respect to the wavelength for laser oscillation. For example, when the active medium of the laser medium 3 is Nd, there are gains in the 0.9 μm band, the 1.06 μm band, and the 1.3 μm band, and the 1.06 μm band, 1.3 μm band, and 0 in descending order of gain. .9 μm band. Here, when it is desired to obtain laser oscillation in the 0.9 μm band, these wavelengths have transmission characteristics so that lasers with high gain in the 1.0 μm band and 1.3 μm band do not oscillate. The desired laser oscillation light in the 0.9 μm band can be obtained by giving total reflection characteristics to the wavelength to be performed, in this case, the 0.9 μm band.

As described above, the total reflection film 6 may have total reflection characteristics with respect to a wavelength band in which laser oscillation is desired, and may have transmission characteristics with respect to other gain wavelengths. With this configuration, there is a feature that laser oscillation light having a desired wavelength can be obtained. Similarly, even when used as a laser amplifier, it may be totally reflected at the wavelength of the laser beam to be amplified and may have transmission characteristics for other wavelengths. By configuring in this way, it is possible to amplify a desired wavelength at which the laser medium 3 has gain. For this reason, there is no extraction of energy by parasitic amplification at other wavelengths, and a high-efficiency, high-power laser amplifier can be obtained.

FIG. 2 is a side view of the planar waveguide laser device including the solid-state laser excitation module of FIG. The pumping light 2 output from the semiconductor laser 1 is incident on the laser medium 3 from one end face 35 of both end faces 35 and 36 in the propagation direction of the laser light traveling while reflecting between the side faces of the laser medium 3, and is in the y direction. And is absorbed by the laser medium 3 while propagating to. The excitation light 2 propagates while spreading, but is reflected by the

clads

4a and 4b having a refractive index lower than that of the laser medium 3, so that it is confined by the

clads

4a and 4b facing each other in the z direction and propagates in the y direction. Similarly, since the laser light incident from the antireflection film 7 is reflected by the

clads

4a and 4b in the z direction, it is confined by the

clads

4a and 4b in the z direction and propagated in the xy plane. Strictly speaking, the propagation direction of the laser light is shifted from the y-axis defined as a predetermined direction because one of the side surfaces is inclined, but here the propagation direction is the same as the y-axis.

Here, a substrate (not shown) may be bonded to the outside of the

clads

4a and 4b. Thus, rigidity can be improved by joining a board | substrate. Further, a heat sink (not shown) may be disposed outside the

clads

4a and 4b or outside the substrate. By arranging the heat sink in this way, the temperature rise of the laser medium can be suppressed, so that high output excitation is possible and high output laser light can be obtained. In addition, when the laser medium 3 has a quasi-3 level, a quasi-4 level, and a 3 level, the gain decreases due to the temperature rise, and therefore it is important to reduce the temperature rise for high efficiency. In this way, by joining the heat sink directly to the

clads

4a and 4b to reduce the thermal resistance and to suppress the temperature rise of the laser medium 3, it is possible to obtain a laser beam with high efficiency and high output.

Embodiment 2. FIG.
3 is a side view of a planar waveguide laser device including a solid-state laser pumping module according to Embodiment 2 of the present invention, viewed from the same direction as FIG. The configuration viewed from above is basically the same as that of FIG. The first cladding 20 is disposed on the xy plane of the laser medium 3, that is, the

main surfaces

31 and 32, respectively, and the

second claddings

4 a and 4 b are disposed outside the first cladding 20. . Here, each refractive index of the first cladding 20 is lower than the refractive index of the laser medium 3, and the refractive indexes of the

second claddings

4 a and 4 b are lower than the refractive index of the first cladding 20. . The pumping light 2 is confined in the z direction between the opposing

second claddings

4a and 4b, and propagates through the combined portion of the laser medium 3 and the first cladding 20 on both sides thereof. On the other hand, since the laser beam is configured to be reflected by the first clad 20, it propagates through the laser medium 3.

With the above-described configuration, the end surfaces 35a and 36a on both sides of the laser beam propagation direction of the solid-state laser excitation module 100 have the laser medium 3 and two first claddings 20 above and below it as the end surfaces to which the excitation light 2 is introduced. The combined end face. For this reason, since the end surface which introduces the excitation light 2 has a large area, the introduction of the excitation light 2 is facilitated. FIG. 3 shows a configuration example using the single-layer semiconductor laser 1, but a stack LD 60 in which semiconductor lasers are stacked in the z direction can be used as shown in FIG. Thus, since the introduction surface of the excitation light 2 can be widened, excitation from the side surface can be easily performed, and a high-output excitation source such as a stack LD can also be used. Here, the excitation light 2 propagating through the first clad 20 and the laser medium 3 is absorbed when passing through the laser medium 3, and propagates without being absorbed by the first clad 20. With this configuration, high-power excitation can be easily performed, so that high-power laser light can be easily obtained.

As a high output pump source (semiconductor laser 1), a broad area LD, an array LD, a stack LD, a single mode fiber, a multimode fiber, a large core fiber, a bundle fiber, or a fiber in which these fibers are arranged in the x direction. An array or the like can be used. Further, in addition to the configuration in which these excitation sources are directly excited close to the side surfaces 33 and 34 of the laser medium 3, the excitation light 2 is condensed by the lens 61 as shown in FIG. It may be introduced from 36a). By configuring in this way, the beam diameter and divergence angle of the excitation light 2 can be arbitrarily adjusted, so that the angle can be adjusted to reflect by the clad. For this reason, since the excitation light can be absorbed by the laser medium 3 with high efficiency, high-efficiency and high-power laser light can be obtained.

Further, as shown in FIG. 20, the beam diameter and divergence angle of the excitation light 2 may be adjusted by a lens group 62 including a plurality of lenses 61. Such a plurality of lenses 61 can minimize the spread of the excitation light due to the aberration, so that the excitation light can be introduced from the end face with higher efficiency. For this reason, high-efficiency and high-power laser light can be obtained.

Further, as shown in FIG. 21, the excitation light 2 output from the stack LD 60 may be collimated by the microlens array 63 and then collectively collected by the lens 61. With such a configuration, the pumping light 2 with higher output can be introduced into the laser medium 3, so that laser light with higher output can be obtained.

Also, as shown in FIG. 22, the pump light 2 that has been collimated is introduced from the wide surface of the tapered slab waveguide 64 and output from the narrow surface, thereby reducing the cross-sectional area. 2 may be used. With such a configuration, the pumping light 2 with higher output can be introduced into the laser medium 3, so that laser light with higher output can be obtained.

Further, as shown in FIG. 23, excitation light 2 having a large divergence angle is introduced from a narrow surface of a tapered slab waveguide 64 and output from a wide surface, thereby reducing the divergence angle. Light 2 may be used. With this configuration, the excitation light 2 can be adjusted to an angle that can be reflected by the clad 20. For this reason, since the excitation light can be absorbed by the laser medium 3 with high efficiency, high-efficiency and high-power laser light can be obtained.

Embodiment 3 FIG.
4 is a side view of a planar waveguide laser device including a solid-state laser pumping module according to Embodiment 3 of the present invention, viewed from the same direction as FIG. The configuration viewed from above is basically the same as that of FIG. The first clad 20 is disposed on one side of the xy plane of the laser medium 3, that is, the main surface 31, and the second clad 4 a is disposed outside the first clad 20. In addition, the second clad 4 b is disposed on the main surface 32 of the laser medium 3 opposite to the first clad 20. With this configuration, the excitation light 2 propagates between the laser medium 3 and the first cladding 20, and the laser light propagates through the laser medium 3.

Further, since the pumping light 2 can be introduced from the end face where the first clad 20 and the laser medium 3 are combined, the end face is enlarged, so that high-power pumping can be easily performed, and high-power laser light can be easily obtained. . Furthermore, the temperature rise of the laser medium 3 can be reduced by bonding a heat sink (not shown) to the lower surface of the second cladding 4. As described above, since the second cladding 4b is directly bonded to the heat sink without sandwiching materials such as the first cladding 20 and the substrate, the thermal resistance can be remarkably lowered, and the temperature rise of the laser medium 3 can be reduced. Can be suppressed. For this reason, a laser beam with higher efficiency and higher output can be obtained.

Embodiment 4 FIG.
5 is a side view of a planar waveguide laser device including a solid-state laser pumping module according to Embodiment 4 of the present invention, viewed from the same direction as FIG. The configuration viewed from above is basically the same as that of FIG. Here, as an example, the first clad 20 is disposed on one surface of the xy plane of the laser medium 3, that is, the main surface 31, as shown in FIG. 4, and the second clad 4 a is disposed outside the first clad 20. In this example, the second clad 4b is disposed on the main surface 32 opposite to the first clad 20 of the laser medium 3. In addition, as shown in FIG. 2, you may apply to the structure which joins the 2nd clads 4a and 4b on the

main surfaces

31 and 32 of the laser medium 3, respectively. Furthermore, you may arrange | position the board | substrate and heat sink which are not shown in figure. Further, as shown in FIG. 3, the present invention may be applied to a configuration in which the first clad 20 is disposed on the

main surfaces

31 and 32 of the laser medium 3. Furthermore, you may arrange | position the board | substrate and heat sink which are not shown in figure.

In this embodiment, among the end faces 35a and 36a at both ends in the predetermined direction (y-axis direction) of the solid-state laser excitation module 100, at least the end faces of the laser medium 3 for introducing the excitation light 2 and the first cladding 20 are used. It is configured to be inclined in the yz plane (a plane perpendicular to the

main surfaces

31 and 32 of the laser medium 3 and along the predetermined direction). The excitation light 2 is introduced from the end faces 35a and 36a and is absorbed when passing through the laser medium 3 while propagating between the

second claddings

4a and 4b. Here, since the end surfaces 35a and 36a are inclined in the yz plane, the two

end surfaces

35a and 36a facing each other and the laser medium 3, or between the end surfaces 35a and 36a and the first cladding 20, or the end surface 35a. , 36a and the second clad 4a, 4b can be eliminated by a parasitic oscillation path confined by total reflection. As described above, since the end faces 35a and 36a are inclined, there is no parasitic oscillation in the yz plane and the parasitic amplification path length can be shortened. Therefore, energy extraction by parasitic oscillation and parasitic amplification can be performed during high output excitation. Since it is small and gain reduction is small, a high-power laser beam can be obtained.

Embodiment 5 FIG.
6 is a side view of a planar waveguide laser device including a solid-state laser excitation module according to Embodiment 5 of the present invention, viewed from the same direction as FIG. The configuration viewed from above is basically the same as that of FIG. FIG. 6 shows a case where the present invention is applied to the configuration shown in FIG. 4 as an example, as in FIG. The configuration of the solid-state laser excitation module 100 is the same as that of FIG. 5, but the position of the semiconductor laser 1 that introduces the excitation light 2 is different. Note that, similarly to the fourth embodiment, the present invention can be applied to the configurations shown in FIGS. Further, a substrate or a heat sink may be arranged.

As in the fourth embodiment, of the end faces 35a and 36a of the solid-state laser excitation module 100, at least the laser medium 3 that reflects the excitation light 2 and the end face of the first cladding 20 are configured to be inclined in the yz plane. ing. The semiconductor laser 1 is disposed so as to introduce the excitation light 2 from the xy plane of the second cladding 4a (the outermost surface of the solid-state laser excitation module 100). The excitation light 2 introduced from the xy plane of the first cladding 4a is reflected by the inclined end surface. The reflected excitation light 2 propagates through the laser medium 3 and the second cladding 4a and is absorbed when passing through the laser medium 3 while propagating. Since the excitation light 2 is thus introduced from the xy plane and reflected by the inclined end face, the inclination angle of the end face can be greatly inclined. For example, the angle can be 45 degrees. Since the inclination angle is increased to about 45 degrees in this way, when the spontaneous emission light generated in the laser medium 3 is totally reflected by the end face, it is not totally reflected by the

second claddings

4a and 4b but is transmitted. For this reason, parasitic oscillation does not occur, and the parasitic amplification path cannot reciprocate the laser medium 3 once. Therefore, even when a higher pumping power is introduced, extraction of energy due to parasitic oscillation or parasitic amplification is small, and gain reduction is small, so that high-power laser light can be obtained.

Embodiment 6 FIG.
FIG. 7 is a top view of a planar waveguide laser device including a solid-state laser excitation module according to Embodiment 6 of the present invention. FIG. 8 is an enlarged view of a region C indicated by a broken line in FIG. 7, and the scale in the y-axis direction is enlarged. In the solid-state laser excitation module 100 of FIG. 7, the position of the side surface 33 attached with the inclination angle θ1 and the side surface 34 extending along the predetermined direction (y-axis direction) is interchanged as compared with the module 100 of FIG. An antireflection film 7 is provided on a part of the side on the 33 side where the side surface interval is wide. The laser reflected light 10 incident on the laser medium 3 from the antireflection film 7 is repeatedly reflected between the side surfaces 33 and 34 facing each other, so that the reflection angle approaches perpendicular to the side surface. The incident angle of the laser incident light 8 on the antireflection film 7 is adjusted so that the incident angle of the laser reflected light 10 immediately before turning back to the side surface 33 or the side surface 34 is not 0, that is, the incident light is not perpendicular to the side surface. By doing so, it is possible to prevent the optical paths from overlapping on the forward path and the return path.

Here, as shown in FIG. 8, when the sum of the incident angle and the reflection angle at the side surface 34 and the side surface 33 of the laser reflected light 10 at the time of turning is θ1, the optical path is inverted between the forward path and the return path. With this configuration, the laser medium 3 that does not pass in the forward path can pass through the return path, so that the beam overlap efficiency is improved, the efficiency of the laser oscillator and the laser amplifier is improved, and the high output laser Light is obtained. In addition, since energy can be extracted efficiently with laser light, the gain remaining in the laser medium 3 is reduced, so that parasitic oscillation and parasitic amplification are less likely to occur. For this reason, it is possible to perform excitation with higher output, and it is possible to obtain laser light with higher output.

According to this configuration, since the forward path and the return path of the laser reflected light 10 in the laser medium 3 are not the same, the optical paths of the laser incident light 8 and the laser output light 9 are not the same. For this reason, since the laser incident light 8 and the laser output light 9 are spatially easily separated, it is not necessary to use a polarization separation means. For this reason, it is possible to reduce the number of components, particularly in a laser amplifier, and the reliability is also improved.

Embodiment 7 FIG.
FIG. 9 is a top view of a planar waveguide laser device including a solid-state laser excitation module according to Embodiment 7 of the present invention. In the solid-state laser excitation module 100 of FIG. 9, the antireflection film 7 that transmits the laser light is provided on a part of the side surface 33 on which the side surface interval is wide, and the other part reflects the laser light and emits the excitation light 2. A narrow-band reflective film 30 that transmits light is applied. A narrow band reflecting film 30 is provided on the entire side surface 34. Two pairs of semiconductor lasers 1 are also provided on the side surface side. As a result, the excitation light 2 is introduced not only from the end faces 35 and 36 of the laser medium 3 but also from the side faces 33 and 34.

For example, when the laser medium is Nd: YAG, the narrow-band reflecting film 30 is designed to reflect the 1064 nm laser beam and transmit the 808 nm or 880 nm excitation light 2. A film having such characteristics can be manufactured by laminating dielectric films. Thus, since it was set as the structure which pumps from four directions of the xy plane of the laser medium 3, higher output pumping is possible and a higher output laser beam can be obtained.

Embodiment 8 FIG.
FIG. 10 is a top view of a planar waveguide laser device including a solid-state laser excitation module according to Embodiment 8 of the present invention. In the solid-state laser excitation module 100 of FIG. 10, the antireflection film 7 a is disposed on a part of the side surface 34 facing the antireflection film 7 on the side surface 33. The antireflection film 7a is a film that transmits laser light. Laser light introduced from the antireflection film 7 into the laser medium 3 propagates while being reflected between the side surfaces 33 and 34. Here, the angle of the laser incident light 8 is adjusted so that the same optical path is not used in the forward path and the return path. For this reason, the laser beam propagating along the return path is not output from the wave antireflection film 7 but is output from the antireflection film 7 a on the opposite side surface 34.

As described above, since the positions of the laser incident light 8 and the laser output light 9 are separated, in the case of a laser amplifier, it is easy to separate the laser incident light and the laser output light. In the case of a laser oscillator, the laser output light 9 that has been amplified through the laser medium 3 can be input to another laser medium 3 or the solid-state laser excitation module 100 for further amplification. As a result, a plurality of laser media or solid-state laser excitation modules can be easily arranged in the resonator of one laser oscillator, and higher-power laser light can be obtained.

Embodiment 9 FIG.
FIG. 11 is a top view of a solid-state laser excitation module of a planar waveguide laser device according to Embodiment 9 of the present invention. The pumping light 2 used in the solid-state laser pumping module 100 in FIG. 11 is, for example, light obtained by collimating fiber output light with a collimating lens (both not shown). The pumping light 2 is generally manufactured by coupling a semiconductor laser beam to a fiber. Alternatively, the output of fiber laser light (not shown) may be used. The excitation light 2 and the laser incident light 8 are introduced from the antireflection film 7 of the laser medium 3 through substantially the same optical path.

The excitation light 2 incident on the laser medium 3 through the antireflection film 7 propagates between the side surfaces 33 and 34 facing each other in the same manner as the laser light and is folded back in the laser medium 3. By configuring in this way, the propagation optical path of the pumping light 2 in the laser medium 3 can be made long, so that the pumping light 2 can be absorbed by the laser medium 3 with high efficiency and with high efficiency and high output. Laser beam can be obtained. Here, when the laser active medium is a quasi-3 level, a quasi-4 level, or a 3 level, it absorbs the laser beam when it is not excited because of the lower level absorption. For this reason, high-density excitation is required to generate a gain for the laser light in the laser medium 3. In other words, when the laser medium 3 contains a large amount of active medium, the high-power excitation light 2 is necessary to generate a gain for the laser light. When the number of active media in the laser medium 3 is small, the excitation output for generating a gain for the laser light may be small.

On the other hand, when the laser medium is small, that is, when the active medium is a low-concentration laser medium 3, the absorption coefficient of the excitation light 2 also decreases. Therefore, in order to keep the absorption rate constant, it is necessary to increase the absorption length. There is. According to the said structure, since the excitation light 2 reciprocates between the side surfaces which have the inclined side surface, absorption length is long. For this reason, even when a low-concentration laser medium 3 is used, a high absorption rate of the excitation light 2 can be obtained. As described above, since the low-concentration laser medium 3 is used, the loss of the pumping light 2 due to lower level absorption is small, and high-efficiency and high-power laser light is obtained. In addition, since the low-concentration laser medium 3 has a small number of active media that generate gain, the gain for the laser light is small. However, in the above configuration, the laser light is reciprocally propagated between the side surfaces having the inclined side surfaces. Long propagation length. For this reason, even when the gain of the laser medium 3 per unit length is small, high-efficiency and high-power laser light can be obtained.

Embodiment 10 FIG.
12 is a top view of a planar waveguide laser device including a solid-state laser excitation module according to Embodiment 10 of the present invention. In the solid-state laser excitation module 100 of FIG. 12, the laser medium 3 is not rectangular, and the side surface 33 is angled in the xy plane with respect to the portion where the antireflection film 7 is provided and the portion where the total reflection film 6 is provided. Is (tilted). Here, the portion provided with the antireflection film 7 on the side surface 33 is at an angle such that the laser incident light and the laser output light of the laser reflected light 10 having substantially the same optical path in the reciprocating optical path are perpendicular to the antireflection film 7. Is attached.

Further, the wavelength conversion element 40 is disposed outside the laser medium 3 and close to the antireflection film 7. The wavelength conversion element 40 is a nonlinear optical material, and may be a nonlinear optical material such as periodic polarization inversion LuNb ₃ (PPLN) or LBO, for example. An incident film 42 is provided on the input side, and an output film 41 is provided on the output side on the end faces of both ends of the wavelength conversion element 40 in the propagation direction of laser light or the like. The output film 41 exhibits reflection characteristics with respect to laser light having a wavelength amplified by the laser medium 3, and exhibits transmission characteristics with respect to wavelength converted light. Further, the incident film 42 on the antireflection film 7 side also shows transmission characteristics with respect to the wavelength of the laser light and the wavelength converted light. With this configuration, the laser light is confined by the reciprocating optical path in the output film 41 and the laser medium 3. When the laser light passes through the wavelength conversion element 40, the wavelength is converted, and the laser light amplified by the laser medium 3 and the wavelength conversion laser light 43 of other wavelengths are obtained. The wavelength conversion laser beam 43 is reflected by the incident film 42 and transmitted through the output film 41 to be output.

In this way, for example, in the laser resonator, the wavelength conversion element 40 is arranged in combination with the laser medium 3 having the above-described configuration to obtain an internal wavelength conversion method. Since the laser medium 3 has a long reciprocal optical path length and no parasitic oscillation or parasitic amplification occurs, high-power excitation is possible, and high-efficiency and high-power laser light can be obtained. Further, laser light that has been wavelength-converted by the internal wavelength conversion method is output, and the laser light that has not been converted is again propagated back and forth through the laser medium 3 and amplified. For this reason, highly efficient and high output wavelength conversion output can be obtained. Here, the wavelength conversion may be the generation of the second harmonic that makes the wavelength of the laser light ½, or the generation of the third harmonic that makes the wavelength １／. Further, it may be converted into a wavelength longer than the wavelength of the laser beam by optical parametric.

Industrial applicability

The solid-state laser excitation module for a planar waveguide laser device according to the present invention can be applied to laser oscillators and laser amplifiers used in many fields.

1 semiconductor laser, 2 excitation light, 3 laser medium, 4a, 4b, 20 clad, 6 total reflection film, 7, 7a wave antireflection film, 8 laser incident light, 9 laser output light, 10 laser reflected light, 30 narrow band Reflective film, 31 and 32, side surfaces 33 and 34, side surfaces, 35 and 36, end face, 40 wavelength conversion element 41 output film, 42 incident film, 43 wavelength conversion laser light, 50 separation means, 51 polarizer, 52 1/4 wavelength plate, 53 Faraday rotator, 54 isolator, 55 1/2 wavelength plate, 60 stack LD, 61 lens, 62 lens group, 63 microlens array, 64 slab waveguide, 100 solid laser excitation module.

Claims

A flat plate-shaped laser medium that propagates the introduced laser beam in a direction along the side surface while reflecting between the pair of side surfaces and amplifies the laser beam between the two sides is provided, and one side surface of the pair of side surfaces extends in a predetermined direction Inclined at a predetermined taper angle with respect to the predetermined direction so that the distance from the other side surface gradually increases, and is introduced into the laser medium from a predetermined location on the wide side of the pair of side surfaces. A plane characterized by propagating a laser beam through the laser medium while reflecting between the side surfaces, and further folding back the laser beam on the side having a narrow side surface spacing and propagating again to the side having a large side surface spacing. Solid-state laser excitation module for a waveguide laser device.
The laser medium has a pair of main surfaces facing along the predetermined direction, the pair of side surfaces on both sides of the main surface, and a pair of end surfaces facing both ends in the predetermined direction,
further,
An antireflection film that transmits at least the laser beam provided in at least one place on the wide side of the pair of side surfaces;
A total reflection film that reflects laser light provided on the pair of side surfaces other than the antireflection film, and
Excitation light introduced to excite the laser medium;
The solid-state laser excitation module for a planar waveguide laser device according to claim 1, comprising:
In order to form a waveguide in a direction perpendicular to the main surface of the laser medium, the laser medium includes a pair of clads disposed on the pair of main surfaces, and in the direction perpendicular to the main surface, the laser light and the excitation light are The solid-state laser excitation module for a planar waveguide laser device according to claim 2, wherein the laser medium propagates between the pair of clads.
A pair of first clads respectively disposed on the pair of main surfaces of the laser medium;
A pair of second claddings disposed respectively outside the pair of first claddings;
The laser light propagates through the laser medium between the pair of first clads, and the excitation light passes through the pair of first clads and the laser medium between the pair of second clads. The solid-state laser excitation module for a planar waveguide laser device according to claim 2, wherein the solid-state laser excitation module propagates.
A first clad disposed on one main surface of the pair of main surfaces of the laser medium;
A pair of second clads respectively disposed on the other main surface of the first clad and the pair of main surfaces;
The laser light propagates through the laser medium between one of the first clad and the pair of second clads, and the excitation light passes through the first clad between the pair of second clads. The solid-state laser excitation module for a planar waveguide laser device according to claim 2, wherein the solid-state laser excitation module propagates through the cladding and the laser medium.
Of the pair of end faces at both ends in the predetermined direction of the solid-state laser excitation module, the portion for introducing the excitation light is inclined in a plane perpendicular to the main surface of the laser medium and along the predetermined direction, 6. The solid-state laser excitation module for a planar waveguide laser device according to claim 2, wherein excitation light is introduced from an inclined end face.
Of the pair of end faces at both ends in the predetermined direction of the solid-state laser excitation module, the portion for introducing the excitation light is inclined in a plane perpendicular to the main surface of the laser medium and along the predetermined direction, The planar waveguide type according to any one of claims 2 to 5, wherein excitation light is introduced from the outermost clad or the second clad and reflected by the inclined end face. Solid state laser excitation module for laser equipment.
A total reflection film provided on a pair of side surfaces of the laser medium is a narrow-band reflection film that reflects laser light and transmits excitation light, and the excitation light is introduced into the laser medium from the side surfaces. A solid-state laser excitation module for a planar waveguide laser device according to any one of claims 2 to 5.
A first antireflection film for introducing the laser beam into a laser medium and a second antireflection film for outputting the laser beam from the laser medium are provided at different locations on the wide side of the pair of side surfaces. The solid-state laser excitation module for a planar waveguide laser device according to any one of claims 2 to 5, wherein the solid-state laser excitation module is used.
6. The planar waveguide laser device according to claim 2, wherein the excitation light is introduced from the antireflection film through an optical path substantially the same as the laser light to perform excitation. Solid-state laser excitation module.
A wavelength conversion element disposed in the vicinity of the antireflection film, wherein the laser beam generated in the laser medium is converted to another wavelength when passing through the wavelength conversion element and outputs a wavelength conversion laser beam; A solid-state laser excitation module for a planar waveguide laser device according to any one of claims 2 to 5, wherein:
6. The laser beam is incident on the antireflection film at an incident angle at which an incident angle of the laser beam on the side surface immediately before the laser beam is folded is not perpendicular to the side surface. A solid-state laser excitation module for the planar waveguide laser device according to claim 1.